METHOD AND APPARATUS FOR THE TRANSPORTATION OF CONCRETE AND THE LIKE MATERIAL IN PIPELINES

Abstract: A method and an apparatus for the transportation of shotcrete and pumped concrete mix of stiff plastic consistency (12) in pipelines (I, II, IV) comprises the injection of a fluid through perforations (10) provided in the pipe (1) surrounding the shotcrete or pumped concrete mix (12) to be transported. The fluid may be compressed air, foam or liquid. Thereby friction between the transported mass and the inside of the pipeline is substantially reduced. The fluid may be guided through the perforations (10) through a mid-pipe-wall space (2) between an outer pipe (4) and an inner pipe (1) or a tube or a system of connected cavities (2A) with perforations (10) spirally implanted in a single-wall pipeline (1 and 4). The pipeline can abruptly rotate for 180 degrees clockwise and conterclockwise with stopping and pausing between turnarounds, providing reduced adhesion and better homogeneity of the mix passing through the pipeline.

Description: METHOD AND APPARATUS FOR THE TRANSPORTATION OF CONCRETE AND THE LIKE MATERIAL IN PIPELINES The invention relates to a method and apparatus for the transportation of shotcrete ' and pumped concrete mix of stiff-plastic consistency in pipelines. During the transportation of shotcrete and pumped concrete mix through the bended outlet tube, flexible or rigid pipeline, high frictional resistance of the vonveyed sticky mix appears. Therefore, it is not possible to transport mixes of the stiff-plastic consistency over large distances. Even over small distances energy consumption for the transportation is excessively high. Furthermore, primarily the shotcrete mix composition is neither uniform nor uniformly distributed over the pipeline cross-section due to gravitation. This fact makes the transport over large distances more difficult. It is therefore an object of the present invention to over¬ come the before-mentioned problems and shortcomings and provide a method as well as an apparatus which makes it possible to transport shotcrete and pumped concrete mix of stiff-plastic consistency over large distances. It is a further object to reduce energy consumption during such transportation. Furthermore, the compounds of the mix composition should be uniformly distributed over the pipe¬ line cross-section when said mix composition leaves the pipe after transportation. These objects are achieved by the features as mentioned in the appended claims. The method according to the invention is characterized by injecting a fluid through perforations provided in the pipe surrounding the shotcrete or pumped concrete mix to be transported. The injected fluid "lubricates" the mix composition inside the pipe, thus, making transportation of shotcrete and pumped concrete mix or stiff-plastic consistency possible and reducing substantially energy consumption. Compressed air, foam or liquid are injected through punctures or small holes densly distributed over the transportation pipe. According to a preferred embodiment of the method according to the invention the fluid is injected with abrupt pressure variations. In case a flexible pipeline is used, the pulsation of the fluid under pressure causes abrupt changes of the inner tube diameter resulting a separation of the mix from the tube wall. This feature furthermore substantially reduces friction between the mix and the inner pipeline wall during transportation. A rotation of the pipeline about its longitudinal axis clockwise and counterclockwise by 180° with stopping and pausing between the turnarounds wet or dry mix passing over the lower side of the tube, turns to the upper side after the turnaround providing a thorough mixing of the compounds. Thus, the compounds of the mix are uniformly distributed over the pipeline cross-section. This procedure enables also the uniform lubrication of the inner pipe¬ line's surface through the small holes. According to one preferred embodiment of the apparatus of the present invention the pipe surrounding the shotcrete or pumped concrete mix to be transported, which is provided with the perforations, is surrounded by an outer pipe with a mid-pipe-wall space, said mid-wall space being in connection with the outer ends of the perforations as well as pressure source for injecting a fluid which may be compressed air, foam or liquid. The mid-pipe-wall space is closed at its ends preferrably with elastic seals and the outer pipe is connected to a lateral hose with a valve for pressure control to the mid-pipe-wall space. According to one embodiment the perforations on the inner pipe are punctured without removing the flexible mass of the pipe. According to another embodiment the small holes may be drilled or formed with removing pipe wall material. Thermally resistant fibers or fiber loops at the outer surface of the inner tube ends and at the inner surfaces at the outer tube ends may be processed in such a way that one part of the fibers or fiber loops is implanted into the rubber mass and another part is uncovered and bound together in the seal space which is limited by a washer and filled with elastic adhesive resin or melted rubber mass. The inner tube ends may have thinner walls from the inner side in which inner rings are to be inserted and fastened to the outer rings and having brackets airtightly pressing the outer tube around the inner tube over the inner rings. According to another embodiment of the apparatus of the invention there is a single-wall pipeline which has a spirally implanted tube inside its single wall or a system of connected cavities with punctures connecting the tube or cavities to the inner space of the pipeline. The tube or the connected cavities have an outside connection to a pressure source for injecting the fluid. In accordance with a further embodiment of the invention the pipeline system is connected to a turning device for rotating the same about its longitudinal axis clockwise and counterclockwise for 180°. Preferrably the middle part is mounted on a rotating bearing ring which has a cogwheel while the cog-transporter device converts mechanical work of a motor into abrupt rotation of the pipeline over the cogwheel with abrupt stopping and pausing. The rotating device with a stable bearing ring is placed at an upper adjustable base stand that can be lifted or lowered with respect to the lower stable base stand of a movable roller. Further features and details of the invention become clear from the following description of different embodiments of the apparatus of the invention with reference to the attached drawings, wherein: Fig. 1 is a schematic sectionial view of the apparatus according to one preferred embodiment of the invention, Fig. 2 a partial longitudinal section of a double-wall pipeline, Fig. 3 a further sectional view of an assembled and sealed double-wall pipeline, Fig. 4 a sectional view of a single-wall pipeline according to another embodiment of the invention, and Fig. 5 a schematic view of the apparatus for the movement of the apparatus according to the invention. As shown in fig. 1 depicting a schematic view of the apparatus for carrying out the invention there is a hopper 0 11 storing concrete mix to be transported to a distant point. A rotation barrel cylinder 12 is filled with concrete mix and a further rotation barrel cylinder 13 discharges the concrete mix into the pipeline. A lateral pipeline 14 introduces compressed air as moving medium 5 pushing the concrete mix through the pipeline. The wet concrete mix passes through the bended outlet tube comprising an inner wall 15 and an outer wall 16. The double-wall bended outlet tube I is provided with an end joint 17. The wet mix further passes through a rigid or !0 flexible double-wall pipeline II, nozzle III for injecting the accelerating admixture (if necessary) and finally through a flexible double-wall pipeline IV. In dry shotcrete transportation double-wall flexible 5 pipeline IV (Fig. 2) is connected after (sometimes before and after) the nozzle for injecting water and liquid accelerating admixture. The bended outlet tube (Fig. 3) that connects the machine 0 and pipeline can be accomplished by double wall. Compressed air is injected through numerous small holes 10 distributed over inner tube 15 wall. Valve 6 regulates the fluid pressure and flow through lateral pipeline 18 connected on outer tube. The bended outlet tube can be disassembled 5 because of cleaning the small holes . Double-wall flexible pipeline (Fig. 3) consists of flexible inner tube 1 provided with reinforcements 31 and outer tube 4. The mid-pipe-walls space 2 is closed with elastic seals 3 at ends of the pipeline. Inner flexible tube 1 has punctures or small holes 10, densely distributed over the wall surface, perpendicular or inclined to the direction of mix path. Outer tube 4 is airtight under the working pressure. Compressed air or foam or lubricating liquid passes through the lateral hose 5 to the mid-pipe-walls space 2. Valve 6 in the position A' or B' (Fig. 3) directs the compressed air into the space 2 or from the space 2 into the space of lower pressure, respectively. Pressures and time intervals between A 1 and B' valve positions, are regulated automatically. Filter 7 stops oils. Lubrication liquid (e.g. superplasticiser or aerating admixture) is injected through injector and lateral pipe¬ line 5 into the mid-pipe-wall space. At the ends of sealed pipeline, the outer side of inner flexible tube 1 and the inner side of outer flexible tube 4 are prepared to form reinforced elastic seals. One part of thermally resistant fibers or fiber loops 32 are implanted into the rubber mass while the other part is protected during the tube fabrication (Fig. 3 - right) or exposed later by dissolving the rubber surface. Before the double- wall pipeline is sealed, the washer 3A is inserted to mid- pipe-walls space 2 and this place is pressed by brackets. Then the pipeline end is set upright to pour the adhesive elastic resin or melted rubber mass into the seals space 3 and left in this position until the mass hardens. Fibers or bounded fiber loops 32 at the end of pipeline walls provide enhanced bond and tensile strenght of the seal 3. Pipeline ends are protected from large deformation by inner ring 30 and outer ring 8. At the assembled pipeline (Fig. 3 - left) inner tube wall is made thinner at the ends. Inner ring 30 of the same inner diameter as the tube, is inserted at the tube end. Outer ring 8 is fastened on the inner ring 30. The outer flexible tube 4 is airtightly pressed to the inner tube 1 with brackets 29 over the inner rings 30. The rigid rings 8 have thicker ands for connecting the afjeacent pipeline by bracket clips. These rings are fastened to the flexible tubes 4 and 1 by screws 9. According to another embodiment of the invention (Fig. 4) there is provided a single-wall pipeline 1 & 4 with a spirally implanted hose or an interconnected system of cavities 2A. The hose or cavities 2A are connected to a pressure source (not shown) for feeding a fluid under pressure. Punctures or small holes 10 connect the hose or cavities 2A to the inside of the single-wall pipeline 1 & 4 in order to reduce the friction between the moving concrete mix and the inner wall. The single-wall pipeline 1 & 4 is provided with reinforcements 31. The pipeline should be mounted from above at roller 33 (Fig. 5). The rotating bearing ring 35, fixed on the pipeline, is mounted over fixed bearing ring 34. Cog-wheel 36 on rotating bearing ring 35 is coupled to the cog- transporter 37 for transferring the movement from motor device into the pipeline rotation for 180 degrees, clock¬ wise and counterclockwise. Motor device is mounted and fixed at upper moveable stand base 38 which can be lifted or lowered in respect to the lower stable stand base 39. The roller 33 with the pipeline can move depending ton the variation of shotcreting position. During rotation, wet mix and lubrication liquid abruptly exchange positions from lower to upper side of the pipeline (Fig. 5). By the injection of compressed air, foam or liquid into the inner space of the flexible origin pipeline in thin jets coming through the densely distributed small holes 10 at the inner tube wall air, foam or liquid jets are being bended in the direction of mixed path due to pressure of the transporting mix. Thus sticky mix is separated from the pipeline wall. The jets are separated later in small air or foam bubbles which are homogenised with the mixed mass. Such aerated mix leaves the pipeline and hits onto the backup surface at high velocity in case of shotcrete or its flow is made smooth before placing in case of pumped concrete. In case of abrupt pressure variation in space 2 or hose or cavities 2A from maximal (valve in position A 1 ) to minimal (valve in position B' ) causes changes of diameter of the flexible pipe which intern causes retraction of sticky mix from the inner pipeline wall. By abrupt rotation of the pipeline around its axis for 180 degrees clockwise and counterclockwise and abruptly stopping with a pause so that the mix passing through the lower part of the pipeline (Fig. 5, position A) exchanges its position with the upper part of the pipeline (Fig. 5, position B) then falling through the middle part of air stream due to gravitation and such uniformy homogenised mix is accelerated by the same amount of air. Where the present invention has been described with reference to certain preferred embodiments various modifications will be apparent to those skilled in the art and any such modifications are intended to be within the scope of the invention as set forth in the appended claims.

Claims: Claims 1. Method for the transportation of shotcrete or concrete mix of stiff-plastic consistency in pipelines, c h a r a c t e r i z e d by injecting a fluid through perforations provided in the pipe surrounding the shotcrete or pumped concrete mix to be transported. 2. Method according to claim 1, wherein said fluid is compressed air. 3. Method according to claim 1, wherein said fluid is foam. 4. Method according to claim 1, wherein said fluid is liquid. 5. Method according to claims 3 or 4 wherein the fluids are mixed with compressed air. 6. Method according to anyone of the preceding claims, wherein said fluid is injected with abrupt pressure variations. 7. Method according to anyone of the preceding claims, wherein the pipe surrounding the shotcrete or pumped concrete mix is turned about its longitudinal axis. 8. Apparatus for the transportation of shotcrete and pumped concrete mix of stiff plastic consistency in pipelines, c h a r a c t e r i z e d by perforations (10) provided within the pipe (1) surrounding the shotcrete or pumped concrete mix, the outside end of said perforations (10) being connected to a pressure source for the injection of a fluid. 9. Apparatus according to claim 7, wherein said pipe (1) is made of flexible materials. 10. Apparatus according to claims 8 or 9 wherein the perforations (10) of the flexible pipe (1) are made without removing pipe mass, i.e. said perforations (10) being punctures. 11. Apparatus according to anyone of claims 8 to 10, wherein the pipe (1) is surrounded by an outer pipe (4) with a mid-pipe-wall space (2), said mid-pipe-wall space (2) being in connection with the outer ends of the perforations (10) and a pressure source. 12. Apparatus according to anyone of claims 7 - 9, wherein the mid-pipe-wall space (2) is closed at its ends with elastic seals (3) and the outer pipe (4) is connected to a lateral hose (5) with a valve (6) for pressure control in the mid-pipe-wall space (2). 13. Apparatus according to claim 12, wherein said elastic seals (3) comprise thermally resistant * fibers or fiber loops (32) at the outer surface of the ends of the inner tube (1) and at the ends of the inner surfaces of the oute tube (4) in such a way that one part of the fibers or fiber loops (32) is implanted into the rubber mass and the other part is uncovered and bound together in the seal space (3) which is limited by a washer (3A) and filled with elastic adhesive resin or melted rubber mass. 14. Apparatus according to claim 13, wherein the inner tube ends have thinner walls from the inner side in which inner rings (30) are to be inserted and fastened to the outer rings (8) and having brackets (29) airtightly pressing the outer tube (4) around the inner tube (1) over the inner rings (30). 15. Apparatus according to claim 7, wherein said pipe surrounding the shotcrete or pumped concrete mix is a single-wall pipeline (1 & 4) which has a spirally implanted tube or a system of connected cavities (2A) inside its single-wall provided with perforations (10) connecting the tube or cavities (2A) to the inner space of the pipeline (1 & 4), said tube or cavities (2A) being connected to a pressure source for injecting a fluid into the inner space. 16. Apparatus according to anyone of claims 7 - 11, wherein the middle part of the pipeline is mounted on a rotating bearing ring (35) carrying a cogwheel (36) while a cog transporter device (37) converts mechanical work of the motor into abrupt rotation of the pipeline over the cockwheel (36), clockwise and counterclockwise for 180 degrees with abrupt stopping and pausing, the rotating device with a stable bearing ring (34) being placed at an upper adjustable base stand (38) which can be lifted or lowered with respect to the lower stable base stand of movable roller (33).

Inventors: JADRIJEVIC ANTE, JADRIJEVIC, ANTE
Applicants: JADRIJEVIC ANTE, MODERNE TEHNOLOGIJE GRADENJA, JADRIJEVIC, ANTE
Application year: 1994
Main classification: B65G53
IPC codes: B65G53